Hydrocele (Pediatric, Testicular) (cont.)

John Mersch, MD, FAAP

Dr. Mersch received his Bachelor of Arts degree from the University of California, San Diego, and prior to entering the University Of Southern California School Of Medicine, was a graduate student (attaining PhD candidate status) in Experimental Pathology at USC. He attended internship and residency at Children's Hospital Los Angeles.

David Perlstein, MD, MBA, FAAP

Dr. Perlstein received his Medical Degree from the University of Cincinnati and then completed his internship and residency in pediatrics at The New York Hospital, Cornell medical Center in New York City. After serving an additional year as Chief Pediatric Resident, he worked as a private practitioner and then was appointed Director of Ambulatory Pediatrics at St. Barnabas Hospital in the Bronx.

What causes hydroceles?

Embryology

Between the 28th and 36th week of gestation, the testes, associated blood vessels and nerves migrate from the upper posterior abdominal wall adjacent to the kidneys to the lower abdominal cavity and through a tunnel (inguinal canal) into the scrotum. As each gonad exits the pelvic region through the inguinal canal into the scrotum, it is preceded by a thinly lined "sack" called the process vaginalis. Once the testes and associated structures have entered the scrotum, the trailing end of the process vaginalis generally closes off, completely isolating the contents of the abdominal cavity and obstructing their passage into the inguinal canal or scrotum. Should this closure be incomplete and the communication narrow, free fluid in the abdominal cavity (peritoneal fluid) may seep into and through the process vaginalis and collect in the scrotum forming a hydrocele. If the connection is larger and a portion of the small intestine migrates out of the abdominal cavity into the inguinal canal and/or scrotum, a hernia has developed.

What are the physical features and types of hydroceles?

A hydrocele is characterized as a non-painful, soft swelling of the scrotum (one or both sides). The overlying skin is not tender or inflamed. There are two types of hydroceles:

communicating, and

non-communicating.

Communicating hydroceles

Communicating hydroceles are present at birth and occur as a consequence of the failure of the "tail" end of the process vaginalis to completely close off. Peritoneal fluid (free fluid in the abdominal cavity) is thus free to pass into the scrotum in which the process vaginalis surrounds the testicle.

A characteristic feature of communicating hydroceles is their tendency to be relatively small in the morning (having been horizontal during sleep) and increase in size during the day (peritoneal fluid drainage assisted by gravity). Actions which increase intra-abdominal pressure (for example, crying, severe coughing, etc.) will also tend to increase the size of the hydrocele.